United States4 Research Articles

Teledentistry in the Recovery Phase of Covid-19: Is it a Reasonable Option for Developing Countries?

Dear Editor, Telehealth as described by the World Health Organization (WHO) is delivering healthcare to a patient by a doctor using media devices when both are far away from each other. Telemedicine has been discussed as a modality to provide better access to health from the early 1990s 1. The recent outbreak of Covid-19 has made this modality a good alternative keeping in mind the comfort and safety of the patient. It has also made it a much more common practice. Recent research has supported the notion that both the service providers and users are highly satisfied by this modality. Teledentistry does not contribute to the progress of disease and is much more cost-effective2. According to a study by Greenhalgh et al., that online video consultation was better suited to people with chronic ailments but surprisingly they played a pivotal role in managing acute conditions also in this Covid-19 pandemic3. Teledentistry has become an integral part of the healthcare system of developed countries such as Australia and the United States4. Teledentistry is a blessing for patients who are COVID positive and need some consultation. It is also fruitful for immunocompromised patients as it saves them from the exposure of the hospital. Also, almost all the dental procedures require close contact on the patient and the dentist so it ensures the safety of both individuals. Patient counseling can be done effectively and all non-invasive procedures can be instructed to the patient. It can also save patient from unnecessary follow up visits. The exchange of written, recorded voice messages and video conversations for the doubts of the patient about the diagnosis and management can also improve the quality of healthcare5.

Prevalence of Gender-Diverse Youth in an Urban School District.

In many studies on gender-diverse youth (GDY), those whose gender identity and sex assigned at birth do not fully align, researchers cite the 2017 Youth Risk Behavior Survey finding that 1.8% of US high school students identify as “transgender.”1 This was the first nationally representative prevalence estimate of GDY and was higher than previous estimates. However, the question assessing gender identity (“Do you identify as transgender?”) likely underrepresents the prevalence of GDY because many do not identify with the word “transgender.” As an alternative, researchers recommend a 2-step question: (1) What was your sex assigned at birth? (2) Which of the following best describes your gender identity?2,3Much of the research involving GDY has been conducted in clinical settings, in which there is a predominance of white and masculine-identified youth.4–7 GDY of color, specifically Black and Hispanic transgender women, are more likely than other gender-diverse people to experience violence and socioeconomic disadvantage because of systemic racism and transmisogyny.8 These systemic inequities likely result in decreased access to gender-affirming care. Because access to gender-affirming care is associated with improved health outcomes,9 identifying groups who are not receiving care is vital to creating more equitable access to care for all GDY, but especially Black and Hispanic transgender women. The goal of this study was to assess the prevalence of GDY in a school-based sample to (1) document the prevalence of GDY by using a 2-step approach and (2) examine prevalence by race and ethnicity and gender identity.In October of 2018, a modified version of the Youth Risk Behavior Survey was distributed to ninth- to 12th-graders in 13 high schools, reaching 91% of the ∼4930 students in a Northeastern midsized city school district. The survey included a 2-step gender identity question: (1) “What is your sex (the sex you were assigned at birth, on your birth certificate)?” with the options “female” and “male” and (2) “Which of the following best describes you (select all that apply)?” with the options “girl,” “boy,” “trans girl,” “trans boy,” “genderqueer,” “nonbinary,” and “another identity.” Of 4730 returned surveys, 37 were found to be unreadable, and 243 were deemed mischievous responders or had <20 answered questions. An additional 1282 participants skipped questions regarding race and ethnicity or gender identity and were excluded from this analysis. Descriptive statistics were calculated by using Stata/SE, version 15.1 (Stata Corp, College Station, TX).Of 3168 surveys analyzed, incongruence between gender identity and sex assigned at birth was identified in 291 participants (9.2%; Table 1). This prevalence was 7.1% among white youth and higher among American Indian, Alaskan Native, Asian American, Pacific Islander, and/or Native Hawaiian, Hispanic, Black, and multiracial youth (13.4%, 14.4%, 9.9%, and 8.7% respectively). Gender identity among GDY was split between masculine (29.9%), feminine (38.8%), and nonbinary identities (31.3%), with 38 (13.1%) selecting >1 identity (Table 2).Nearly 10% of high school students surveyed reported a gender-diverse identity. The prevalence of GDY in this study is 5 times higher than current national estimates from a study involving 10 states and 9 urban school districts.1 Although these data were collected from a single urban school district, the findings may approximate a less biased estimate of the prevalence of youth with gender-diverse identities, given how gender identity was operationalized.Additionally, the demographics of GDY in this school-based study differ from those of GDY accessing gender-affirming care in the same region. A 2018 survey from the only pediatric gender clinic in the region found the majority of patients identified as white (88%) and masculine (65%).10 This clinic’s findings are consistent with other pediatric gender clinics across the United States4–7 and highlight the lack of diversity among youth receiving gender-affirming care, especially with respect to race and/or ethnicity and gender. These disparities suggest that gender clinics may not be reaching youth at the highest risk of experiencing violence, victimization, socioeconomic disadvantage, and health disparities: Black and Hispanic transgender women. Researchers should consider using a 2-step approach, as outlined above, to better reflect prevalence of GDY, particularly in statewide and national level surveys, with sample sizes allowing analysis of potential differences in gender identity by race and/or ethnicity and age. In addition to encouraging continued refinement of gender identity measures, particularly for youth, these findings underscore the need to re-evaluate systems and structures that continue to perpetuate inequities in access to gender-affirming care.We thank the Allegheny County Health Department for their role in data collection and for the use of these data. We are grateful to Pittsburgh Public School Board leadership for their collaboration.

New Challenges in Addiction Medicine: COVID-19 Infection in Patients With Alcohol and Substance Use Disorders-The Perfect Storm.

New Challenges in Addiction Medicine: COVID-19 Infection in Patients With Alcohol and Substance Use Disorders-The Perfect Storm.

Setbacks in Implementing the Renewable Fuel Standard Lead to Calls for Reform

Biotechnology Law ReportVol. 35, No. 6 The Holman ReportSetbacks in Implementing the Renewable Fuel Standard Lead to Calls for ReformChristopher M. HolmanChristopher M. HolmanSearch for more papers by this authorPublished Online:1 Dec 2016https://doi.org/10.1089/blr.2016.29033.cmhAboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetailsCited byInfrastructure to enable deployment of carbon capture, utilization, and storage in the United States4 September 2018 | Proceedings of the National Academy of Sciences, Vol. 115, No. 38 Volume 35Issue 6Dec 2016 InformationCopyright 2016, Mary Ann Liebert, Inc.To cite this article:Christopher M. Holman.Setbacks in Implementing the Renewable Fuel Standard Lead to Calls for Reform.Biotechnology Law Report.Dec 2016.249-257.http://doi.org/10.1089/blr.2016.29033.cmhPublished in Volume: 35 Issue 6: December 1, 2016PDF download

The Promise of Leisure-Time Physical Activity to Reduce Risk of Cancer Development.

Cancer is among the leading causes ofmorbidity andmortality worldwide, with 14.1 million new cancer cases and 8.2 million cancer-related deaths in 2012.1(p3) By 2030 the global cancer burden is expected to double,with21.7millionnew cases and 13.2million cancer deaths projected due to demographic changes alone.1(p3) These estimateswill likely be compounded by the trend toward unhealthy lifestyle behaviors (eg, smoking and poor diet), particularly in emerging economies.Given that large increases in cancer incidence and mortality are expected tooccur indeveloping countrieswhere economic resources for secondaryandtertiarycareare low,primarypreventive strategies for cancer risk reductioncouldhelp to decrease the worldwide cancer burden. Asignificantproportionofcancerscouldbeprevented,and behavioral interventionsmayoffer themostcost-effective longtermcancer control options.Well-knownapproaches include tobacco use cessation, immunization against or treatment of cancer-causing infectious agents, and limiting excessive sun exposure.TheWorldCancerResearchFundestimates that20% to 25% of cancers are related to positive energy balance including overweight/obesity, poor nutrition, and/or physical inactivity.1(p6) Given that almost one-third of adults are inactive, and the proportion of inactivity appears to be increasing in low-income countries,2 physical activitymay be an important, potentially modifiable cancer risk reduction strategy. There have beennumerous studies reporting on the association between physical activity and cancer. These studies, primarily conducted in cancers of the lung, breast, prostate, colon/rectum and endometrium, show a 10% to 40% cancer risk reduction when themost physically active study participantswere comparedwith the least active participants. However, the types of physical activity (ie, leisure time, occupational, household)havevariedacross studies, anddue to small numbers, associationswith certain rare cancers are largelyunknown. Furthermore, potential modification by body size is unresolved and could be important for understanding causal associations, as well as making public health recommendations for lowering risk. The pooled analysis presented byMoore et al3 in this issue ofJAMAInternalMedicinewasundertakentodeterminethecancer risks associatedwith leisure-time physical activity and potential heterogeneity by smoking and body size. Their approach, focusing on 26 different cancer types and exploration of bodymass index (BMI, calculated asweight in kilogramsdivided by height in meters squared) as both a confounder and modifier of thephysical activity–cancer association, is innovative and provides clarity to the potentially important role of leisure-time activity in cancer prevention. One of the most important contributions of the pooled analysis undertaken by Moore and colleagues3 is the improved statistical precision to examine the physical activity– cancer association among rare malignant neoplasms. In this robust study, theauthorswereable todemonstrate that leisuretime activity was associated with reduced risk of approximately half of the cancer types examined (including 3 of the 4 cancersmost commonlydiagnosedamongmenandwomen worldwide). Furthermore, for more than one-quarter of cancer types, physical activity was associated with greater than 20% risk reduction. Importantly, the investigators controlled forwell-knowncancer-relatedrisk factorsandmoststudies (approximately 80%) used validatedmeasures of physical activity. Although this analysiswas limited to 1 type of physical activity (ie, leisure time), the evidence available todate suggests that it is unlikely that accounting for other sources (ie, occupational, transportation, and daily living) would substantially alter the findings. Another important aspect of the investigation by Moore et al3 was the examination of BMI as both a potential confounder and effectmeasuremodifier. On adjustment for BMI, associationswithphysical activitywere attenuated to thenull for 3 cancer sites (liver, gastric cardia, and endometrium), but for the remaining 10 sites associations with physical activity persisted. Moreover, after stratifying by BMI (<25 vs ≥25) the authors report significantheterogeneity (P < .01) foronly2cancer sites (lungandendometrium). Interestingly, significant risk reductionsassociatedwith increasedphysical activitywereobserved among participants with BMI of 25 or greater for both lung and endometrial cancer. Considering the fact that approximately 70% of adults in the United States4 and 40% of adults worldwide5 are overweight or obese, physical activity may serve as a promising risk reduction strategy, even among this demographic category.Moore and colleagues3 are among the first to provide evidence suggesting that, for some cancers, physical activity may act together with obesity to influence carcinogenesis. Theprecisemechanismsbywhichphysical activity influences carcinogenesis are unknown. Resolving these underlyingmechanismsshouldbeahigh researchprioritybecause this information would not only strengthen the biological plausibility of the physical activity–cancer association but could aid in identifying molecular targets for intervention. Additional research isneededto formallyevaluatewhether associations are mediated by BMI or other indices of body weight.WhereasBMI is a commonlyusedmeasureof total adiposity, other indicators (eg, waist-to-hip ratio and weight change, particularly in adulthood) may better measure central adiposity or visceral fat,which ismetabolically active and could play an integral role in tumor initiation and progresRelated article page 816 Research Original Investigation Leisure-Time Physical Activity and Risk of 26 Types of Cancer

Increased frequency of extreme La Niña events under greenhouse warming

Extreme La Nina events occur when cold sea surface temperatures across the central Pacific Ocean create a strong temperature gradient to the Maritime continent in the west. This work projects an increase in frequency of La Nina events due to faster land warming relative to the ocean, and a greater chance of them occurring following extreme El Nino events. The El Nino/Southern Oscillation is Earth’s most prominent source of interannual climate variability, alternating irregularly between El Nino and La Nina, and resulting in global disruption of weather patterns, ecosystems, fisheries and agriculture1,2,3,4,5. The 1998–1999 extreme La Nina event that followed the 1997–1998 extreme El Nino event6 switched extreme El Nino-induced severe droughts to devastating floods in western Pacific countries, and vice versa in the southwestern United States4,7. During extreme La Nina events, cold sea surface conditions develop in the central Pacific8,9, creating an enhanced temperature gradient from the Maritime continent to the central Pacific. Recent studies have revealed robust changes in El Nino characteristics in response to simulated future greenhouse warming10,11,12, but how La Nina will change remains unclear. Here we present climate modelling evidence, from simulations conducted for the Coupled Model Intercomparison Project phase 5 (ref. 13), for a near doubling in the frequency of future extreme La Nina events, from one in every 23 years to one in every 13 years. This occurs because projected faster mean warming of the Maritime continent than the central Pacific, enhanced upper ocean vertical temperature gradients, and increased frequency of extreme El Nino events are conducive to development of the extreme La Nina events. Approximately 75% of the increase occurs in years following extreme El Nino events, thus projecting more frequent swings between opposite extremes from one year to the next.

Progress in the understanding and management of pulmonary arterial hypertension.

In 1981 the “Patient Registry for the Characterization of Primary Pulmonary Hypertension” was set up, supported by the National Heart, Lung and Blood Institute, and recruited 194 patients across 32 clinical centres over 4 years in the United States1,2. The estimated median survival of these incident cases of primary pulmonary hypertension (which approximates to what we would now term idiopathic pulmonary arterial hypertension, IPAH) was 2.8 years, with a 68% survival rate at 1 year, 48% at 3 years and 35% at 5 years1. Since 2000 a number of national registries have been set-up across the world to study the developing epidemiology of pulmonary arterial hypertension (PAH)3. The largest of these is the REVEAL (Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management) Registry in the United States4. Between 2006 and 2009, 2635 prevalent and incident cases were included in survival analysis across 55 centres. For IPAH, there was a 91% survival rate at 1 year, 74% at 3 years and 65% at 5 years4. The Spanish registry also recruited 866 prevalent and incident cases of IPAH between 2007 and 2008 and calculated 1-, 3- and 5-year survival rates of 87%, 75% and 65% respectively5. In the French registry, which also analysed prevalent and incident cases, for a sub-population of 190 patients with IPAH, hereditary PAH (HPAH) and anorexigen-associated PAH cases (which all have similar baseline characteristics and outcomes) between 2002 and 2003, a 1-year survival rate of 83% and 3-year of 58% was calculated6,7. In the UK there was a focus on incident cases, and 482 patients with IPAH, HPAH, and anorexigen-associated PAH were included between 2001 and 2009 and had 1-, 3- and 5-year survival rates of 93%, 73% and 61% respectively8. Although there is debate about the inclusion of both prevalent and incident cases in these registries (owing to survivor bias), there is broad agreement over current survival rates across these registries. Measurable progress has been made in the management of pulmonary arterial hypertension over the last 33 years – now, at 5 years, a larger proportion of people are living with the disease, rather than dying from it. In this review article we take a historical approach to reflect on the journey that has brought us to where we are today, focussing on the key milestones in the management of pulmonary arterial hypertension, signposted by the World Health Organisation (WHO) “World Symposia in Pulmonary Hypertension”. It will become apparent that this mirrors the developments and movements in medicine over the last 150 years: from pathology to physiology, from physiology to pharmacology, from pharmacology to cell biology, from cell biology to genetics9.

How Availability and Accessibility of Gambling Venues Influence Problem Gambling: A Review of the Literature

How Availability and Accessibility of Gambling Venues Influence Problem Gambling: A Review of the Literature

ChemInform Abstract: Chemical Removal of Nitrate from Water

HIGH levels of nitrate in ground water can pose a serious health risk. Reduction of nitrate to nitrite in the gut may cause methemoglobinaemia1both in newborn infants and in adults deficient in glucose-phosphate dehydrogenase2. Under abnormal circumstances, reduction to nitrite can also occur in the stomach to form N-nitrosamines, a postulated cause of stomach cancer3. Nitrate outflow onto shallow continental shelves can promote nearshore algal blooms. Both natural and anthropogenic sources contribute to nitrate pollution. In the United States4 and Europe5, legislation now specifies a maximum permissible nitrate level in drinking water. Techniques such as selective ion exchange6, reverse osmosis, electrodialysis and distillation exist to transfer nitrate between two bodies of water, but only biological processes are presently available for nitrate destruction. Here I describe a chemical process in which aluminium powder reduces nitrate to ammonia, nitrogen and nitrite. In a pH range of 9 to 10.5, selective reduction of nitrate relative to sulphate is possible, and between pH 9.1 and 9.3, loss of the reductant through decomposition of water can be minimized to less than 2%. Subsequent control of pH and concentrations of dissolved aluminium, nitrite and ammonia should be possible at a realistic cost, making this process potentially useful for combating nitrate pollution.

Implementation and Application of a Community Total Joint Registry

The Swedish Knee Arthroplasty Register, a prospective national study of total knee arthroplasty that was begun in 1975, and the corresponding Swedish National Hip Register, which was begun in 1979, have had a dramatic impact on joint arthroplasty in that country and have received increasing attention and imitation in recent years1-7. Sharing registry information with surgeons has been an important factor in allowing Sweden to have a rate of revision hip replacement of approximately 8% compared with 18% in the United States4. Such results, as well as the rapid proliferation of arthroplasty options and some notable failures of new technology, have prompted calls for a national joint registry in the United States4. While even the founders of the Swedish registry acknowledge that a prospective, randomized clinical trial is the so-called gold standard for comparing new prosthetic designs8, widespread adoption of such trials seems impractical in the United States for a number of reasons. The general goals of a joint registry (defining the epidemiology of joint replacement surgery, providing timely information about outcomes to the orthopaedic community, and identifying risk factors for poor outcomes) remain unchanged regardless of whether the registry is community-based or implemented at the national level4. We began our community-based total joint registry in 1991, with a database that allowed us to track implant use and failure rates among the forty-four orthopaedic surgeons doing joint arthroplasty in a community health-care system, and with the knowledge that a majority of primary hip arthroplasties in the United States are performed by relatively low-volume surgeons9. Although we were interested in monitoring implant costs, it became immediately apparent that our registry would provide us with valuable information with regard to implant failures in the hands of community surgeons …

Nonoperative Treatment of Vertebral Blastomycosis Osteomyelitis Associated with Paraspinal Abscess and Cord Compression: A Case Report

Fungal infections of the spine are uncommon and usually result from hematogeneous spread of a primary focus1. Blastomyces dermatitidis has been described as a causative agent in cases of vertebral osteomyelitis2,3. Most cases of blastomycosis osteomyelitis begin as primary fungal infections of the lungs3. However, traumatic innoculation, local extension, and lymphatic spread also have been described as possible mechanisms of introduction of the fungi to bone2. The long bones are more commonly affected than the vertebral column is4. Primary cutaneous blastomycosis can occur5, and many other organ systems, including the genitourinary and central nervous systems, can be affected6. Blastomyces dermatitidis is a dimorphic fungus endemic to the southeastern and south central portions of the United States4. Primary pulmonary blastomycosis is acquired by inhalation of airborne conidia1. The spores then develop into the yeast form, producing an acute illness stage that is clinically indistinguishable from a bacterial pneumonia. In as many as 50% of cases of disseminated blastomycosis, osseous involvement may occur2,7. We report the case of a patient in whom vertebral blastomycosis osteomyelitis was successfully treated nonoperatively. The patient was informed that information concerning this case would be submitted for publication. Asixty-four-year-old South American woman who had recent-onset midthoracic spinal pain with left scapular radiation presented to us in February 2001. The patient had no history of trauma or recent illness and no history of exposure to farm animals or pets. The medical history included chronic hypertension, arthritis, and depression. Physical examination revealed normal findings. A computerized tomography scan demonstrated a paraspinal mass with rim …

Acute Heart Failure Syndromes

Acute heart failure syndromes (AHFS) poses unique diagnostic and management challenges. This syndrome has recently received attention from researchers, clinicians, regulatory agencies, and the pharmaceutical industry. However, there is no consensus on its definition, epidemiology, pathophysiology, appropriate therapeutic options, and directions for future research. This document is the result of the First and Second International Workshop on Acute Heart Failure Syndrome that took place in May 2004 and April 2005. At these workshops, a selected group of physician scientists, epidemiologists, clinicians, regulatory and governmental funding agencies, and industry representatives from North and South America and Europe convened to develop a platform for future investigative approaches and management of AHFS. Subsequently, emergency physicians, who play a pivotal role in the early management of AHFS, contributed to this document. AHFS is defined as gradual or rapid change in heart failure (HF) signs and symptoms resulting in a need for urgent therapy. These symptoms are primarily the result of severe pulmonary congestion due to elevated left ventricular (LV) filling pressures (with or without low cardiac output). AHFS can occur in patients with preserved or reduced ejection fraction (EF). Concurrent cardiovascular conditions such as coronary heart disease (CHD), hypertension, valvular heart disease, atrial arrhythmias, and/or noncardiac conditions (including renal dysfunction, diabetes, anemia) are often present and may precipitate or contribute to the pathophysiology of this syndrome.1–3 HF hospitalizations have risen steadily, with >1 million in 2004 in the United States4; a similar number has been reported in Europe. In the United States, it is estimated that these hospitalizations account for >75% of the 46 billion dollars spent each year on the care of HF patients.4 Although much has been accomplished in the management of chronic HF, the absence of evidence-based clinical practice guidelines for AHFS is striking in comparison to …

Current status of revision total knee arthroplasty: how do we assess results?

Failure of primary total knee arthroplasty within five years after the operation most frequently occurs because of deep infection (38%), instability (27%), failure of bone ingrowth into a cementless implant (13%), patellar problems (8%), wear (7%), loosening (3%), or miscellaneous problems (4%)1. In contrast, in a series of 427 revision total knee arthroplasties, failure of fixation was the most frequent problem, followed by abnormal alignment, component malposition, osseous fracture, and patellar problems2. The results of revision total knee arthroplasty are difficult to assess because they are influenced by many factors: the etiology of failure, the extent of bone loss, the quality of the soft tissues, the technique of reconstruction, the adequacy of rehabilitation, patient compliance, the duration of follow-up, and the mode of assessment. Contemporary modular designs have provided good short-term results. A combined review of 161 revisions that had been performed with a modular constrained condylar knee or posterior stabilized design revealed an 80% rate of good or excellent results after an average duration of follow-up of 3.5 years, with a 33% prevalence of radiolucent lines and a 10% rate of complications3. The durability of the results will depend in part on the integrity of the locking mechanisms of the modular components, the quality of the polyethylene, and the load transfer conferred by modular stems and augments to the implants. Long-term studies will be necessary to determine if these modular designs are more durable than nonmodular prostheses. Successful revision total knee arthroplasty requires careful preoperative analysis and planning to ensure that the cause of failure is known and that the necessary instruments, implants, and other supplementary reconstructive materials are available. In 1995, 243,919 primary total knee arthroplasties and 169,803 primary total hip arthroplasties were performed in the United States4. As a …

Lesions associated with postweaning multisystemic wasting syndrome in pigs from Prince Edward Island, Canada.

Postweaning multisystemic wasting syndrome (PMWS) is a recently recognized swine disease originally reported in western Canada.2,9 Retrospective postmortem studies revealed that this condition first appeared in 1991, but it was not recognized as a specific disease until 1996.9 A similar syndrome has been described recently in pigs from the United States4,11 and Europe.1 The etiology of this syndrome is still under investigation, but porcine circovirus (PCV), a member of the family Circoviridae that includes chicken anemia virus, psittacine beak and feather disease virus, and a newly described pigeon circovirus,15 is thought to play an important role in the pathogenesis of this condition. The purpose of this paper is to describe and illustrate the most common microscopic findings associated with PMWS in pigs and to report the presence of PMWS in swine herds from Atlantic Canada. Six pigs, 5–12 weeks of age, from four swine herds located in Prince Edward Island were submitted to the Atlantic Veterinary College for postmortem examination. Five pigs were alive and one (pig no. 3) had been found dead in its pen. Pig nos. 2 and 3 and pig nos. 5 and 6 were herdmates. All pigs had a history of weight loss, dyspnea, and/or scouring, first noticed 1 or 2 weeks after weaning. Blood samples were obtained from live pigs prior to euthanasia. Complete postmortem examination was performed, and tissues were selected for histopathology, bacteriologic culture, and virologic analysis. Tissues for histopathology were fixed in 10% neutral buffered formalin, embedded in paraffin, cut at 5 mm, and stained with hematoxylin and eosin. In two cases, formalin-fixed tissue was fixed in 2% glutaraldehyde and postfixed in 1% osmium tetroxide, dehydrated in a graded series of ethanol, and infiltrated and embedded in epon/araldite for sectioning and examination by transmission electron microscopy. Thin sections were stained with a saturated solution of uranyl acetate and Sato lead stain. Tissues from five pigs (nos. 1, 2, 3, 5, and 6) were sent to the Veterinary Services Branch of Manitoba Agriculture for the detection of pathogenic PCV by polymerase chain reaction (PCR).8 Porcine reproductive and respiratory syndrome (PRRS) serology was done on serum of two pigs by an indirect fluorescent antibody test (IFAT) that was developed in house. Gradual dilutions of the test serum were made and reacted with PRRS virus (PRRSV)-infected MARC cells, washed, mounted, and evaluated by fluorescent microscopy. Lungs from three pigs and lymph nodes from two others were tested for the pres-

Chemical removal of nitrate from water

HIGH levels of nitrate in ground water can pose a serious health risk. Reduction of nitrate to nitrite in the gut may cause methemoglobinaemia1both in newborn infants and in adults deficient in glucose-phosphate dehydrogenase2. Under abnormal circumstances, reduction to nitrite can also occur in the stomach to form N-nitrosamines, a postulated cause of stomach cancer3. Nitrate outflow onto shallow continental shelves can promote nearshore algal blooms. Both natural and anthropogenic sources contribute to nitrate pollution. In the United States4 and Europe5, legislation now specifies a maximum permissible nitrate level in drinking water. Techniques such as selective ion exchange6, reverse osmosis, electrodialysis and distillation exist to transfer nitrate between two bodies of water, but only biological processes are presently available for nitrate destruction. Here I describe a chemical process in which aluminium powder reduces nitrate to ammonia, nitrogen and nitrite. In a pH range of 9 to 10.5, selective reduction of nitrate relative to sulphate is possible, and between pH 9.1 and 9.3, loss of the reductant through decomposition of water can be minimized to less than 2%. Subsequent control of pH and concentrations of dissolved aluminium, nitrite and ammonia should be possible at a realistic cost, making this process potentially useful for combating nitrate pollution.

The Role of the American Judiciary in the Extradition of Political Terrorists

political offense exception exists in the extradition treaty between the United States and Israel.2 He claimed Israel sought his extradition because of his past association with the Palestine Liberation Organization and in any event, the bombing was a political act aimed at the State of Israel. Following a lengthy hearing, a federal magistrate in Chicago found probable cause existed to extradite Abu Eain and the charged offenses did not fall under the political offense exemption.3 Six months earlier Peter Gabriel John McMullen successfully raised the same defense when Great Britain sought his extradition from the United States4 for involvement in the 1974 bombing of a British Army Installation in England by the Provisional Irish Republican Army.5 The federal magistrate concluded this bombing was part of a political disturbance and was directed at the British army-a prime target for guerilla warfare.6 These cases illustrate a highly intricate extradition jurisprudence. The political offense exemption is found in virtually every modern treaty of extradition and its application calls for findings of fact and conclusions of law concerning crimes, events, and political situations halfway around the world. In Abu Eain, for example, the magistrate declined to take judicial notice that there is now, and has existed for more than three decades, a military and political conflict between the government of Israel and the several Arab states and the people of Palestine.' In McMullen, however, the magistrate did take notice an insurrection and a disruptive uprising of a political nature existed in Northern Ireland in 1974.8 * Professor of Law, Northwestern University; B. A., Northwestern University; J. D., University of California at Berkeley. ** B. S., Columbia College; J. D. Northwestern University, 1978. 1 The bombing occurred on May 14, 1979. Tiberias is a resort area on the Sea of Galilee. The area was unus-

The Function of Today's Doctoral Programs

The Function of Today's Doctoral Programs

Discovery of amphibians in the Namurian (Upper Carboniferous) of Fife

CARBONIFEROUS amphibians are very rare as fossils and almost all major finds of British specimens were made in the nineteenth century. Nevertheless, knowledge of Carboniferous tetrapods, both amphibians and reptiles, has expanded considerably in recent years1,2. All are from Europe or North America and most are from horizons equivalent to or later than the British Coal Measures (Westphalian and Stephanian, respectively). Far fewer amphibians are known from the Lower Carboniferous and knowledge of the Namurian tetrapod fauna, between the Lower Carboniferous and the Coal Measures, is even more meagre. With the exception of a single incomplete anthracosaur amphibian from the Namurian of the Ruhr, Germany3, pre-Coal Measure amphibia are known from only three areas (1) West Virginia and south-western Pennsylvania in the United States4,5; (2) Nova Scotia, Canada6, and (3) the Edinburgh area and southern Fife in Scotland7,8. In November 1974, however, fossil amphibian and fish remains were discovered at the Dora Opencast Site (area C), south-east of Cowdenbeath, Fife (Fig. 1), in Carboniferous strata of Namurian age. The richly fossiliferous bone bed at Cowdenbeath formed a localised patch in a seatrock (rooty, muddy siltstone), which lies beneath a coal seam below the Lochgelly Blackband Ironstone. The Lochgelly Blackband Ironstone itself has also produced a fauna with amphibian remains in the Dora site, while a few specimens have been recovered from strata up to 6 m lower in the sequence.

Postwar Cyclical Fluctuations in Income and Employment: Southeast and United States

The current preoccupation of economists with problems of economic growth on a national and regional level, abetted by a moderately expanding body of economic data by region and state for the United States, has increased the output of research bearing on the southern United States, a widely-acknowledged laggard region.1 In those regional studies which focus on comparative changes in income and employment, explicit or implicit emphasis is placed on an industrial composition, or industry-mix, in accounting for the unsatisfactory economic performance of the South.2 Regarded as particularly is the region's specialization in industries utilizing large amounts of relatively unskilled labor, or in industries characterized simply as slow growth. We shall comment at some length on what we term this unfavorable industrymix thesis in a subsequent section of this paper. Below, we set out some results of a comparative study of cyclical fluctuations in the Southeast3 and the United States4

Relationship between Relative Turgidity and Diffusion Pressure Deficit in Leaves

A PRACTICAL field-method for measuring water deficits in plants has been described1 in which the water content of samples of leaf disks is measured and compared with that of parallel samples rendered fully turgid by floating on water. The field-water content expressed as a percentage of the turgid water content was called the ‘relative turgidity’. This technique and mode of expression have proved successful in studying the ecology of a variety of plants in Uganda2, Israel3, the United States4 and Australia5. It is, however, difficult to assess the full significance of relative turgidity values without a knowledge of their equivalence in terms of ‘diffusion pressure deficit’. For example, 80 per cent relative turgidity in different species might mean quite different degrees of ‘water stress’ expressed as the diffusion pressure deficit of the leaves.