text stringlengths 59 1.12k |
|---|
the virus. Individuals with a discordant response usually exhibit high numbers of mutations against the nucleoside drug class, which often includes the M184V mutation. This specific mutation of M184V (refers to a change in the amino acid switch in HIVs viral gene strand) is most known for being the tell-tale sign of 3T... |
associated with sustained responses to antivirals, confirmed in several studies. Generally, cross-resistance would be a concern. Mutations that resist one drug may also resist another, especially one in the same drug class. This may lower the efficacy of new drugs which a patient has never taken before. However, if one... |
nucleosides such as ddI, d4T, ddC or abacavir (Videx, Zerit, Hivid or Ziagen). Also, the M184V seems to result in re-sensitization of the virus to AZT (Retrovir) in patients who previously developed resistance to AZT. Finally, the presence of 184V in highly experienced patients is associated with a better antiviral res... |
other factors are at play in discordant responses to HAART (highly active antiretroviral therapy). These include drug resistance mutations, replicative capacity and immunologic aspects. The initial status of the patient, including CD4 T-cell count and presence of the 184V mutation before antiviral treatment, is predict... |
damaged ones immune system has become prior to treatment, the more difficult it may be for the immune system to assist in suppressing viral load later. Often, T-cells remain stable or rise despite not obtaining optimally suppressed viral loads because HIV (though resistant) becomes weakened by antiviral drugs, impairin... |
In other words, the antiviral treatments cause a decreased replicative capacity of the virus. In fact, there is a firm relationship between the high numbers of mutations and decreased replicative capacity of virus from people with discordance. The disconnect syndrome can be explained in an alternative way. The M184V an... |
type is virus that has not mutated, seen usually in non-treated individuals.) The less fit the virus, the less able it is to overcome the effects of other antivirals. Additionally, the reverse transcriptase enzyme, which HIV uses to reproduce itself, is also crippled despite the presence of resistance, and thus becomes... |
its DNA strand (viral gene), and is therefore unable to replicate. Finally, development of increased mutations does not interfere with immune recovery during HAART. Measured by immune cell proliferation and response to interleukin 15 (a specific cytokine, protein produced by immune cells used for research purposes to m... |
and colleagues, 9th Retroviruses Conference, Seattle, February 2002). Without attempting to advise whether patients in a disconnect situation should change or continue their treatment, the questions invoked here are placed on the table. The presence of primary resistance mutations can oddly enough be associated with th... |
is facing this discordant predicament, the next path may not be always clear. Phenomena are occurring in the disconnect syndrome that are below the surface. A patients decisions are often complicated by various confounding issues. This is compounded by the fact that data regarding the long-term outlook of patients cont... |
while others concluded that the immunologic deterioration is delayed by an average of three years (Stephen Deeks and colleagues, University of California at San Francisco). However large trials of disconnected patients who continue to maintain good clinical immunologic response to HAART for a specified duration would p... |
stable clinically and not developing opportunistic infections. However, with the ongoing epidemic of resistance, it would be helpful to understand what it all means to a patients health and longevity. Daniel S. Berger, M.D. is Medical Director for NorthStar Healthcare; Clinical Assistant Professor of Medicine at the Un... |
In mathematics, hyperbolic functions are analogs of the ordinary trigonometric, or circular, functions. The basic hyperbolic functions are the hyperbolic sine "sinh" (typically pronounced /ˈsɪntʃ/ or /ˈʃaɪn/), and the hyperbolic |
are the area hyperbolic sine "arsinh" (also called "asinh", or sometimes by the misnomer of "arcsinh") and so on. Just as the points (cos t, sin t) form a circle |
with a unit radius, the points (cosh t, sinh t) form the right half of the equilateral hyperbola. Hyperbolic functions occur in the solutions of some important linear differential equations, |
for example the equation defining a catenary, and Laplace's equation in Cartesian coordinates. The latter is important in many areas of physics, including electromagnetic theory, heat transfer, fluid dynamics, and |
special relativity. Hyperbolic functions were introduced in the 18th century by the Swiss mathematician Johann Heinrich Lambert. The hyperbolic functions are: Via complex numbers the hyperbolic functions are related to |
the circular functions as follows: where is the imaginary unit defined as . Note that, by convention, sinh2x means (sinhx)2, not sinh(sinhx); similarly for the other hyperbolic functions when used |
with positive exponents. Another notation for the hyperbolic cotangent function is , though cothx is far more common. Hyperbolic sine and cosine satisfy the identity which is similar to the |
Pythagorean trigonometric identity. It can also be shown that the area under the graph of cosh x from A to B is equal to the arc length of cosh x |
from A to B. For a full list of integrals of hyperbolic functions, see list of integrals of hyperbolic functions In the above expressions, C is called the constant of |
integration. It is possible to express the above functions as Taylor series: A point on the hyperbola xy = 1 with x > 1 determines a hyperbolic triangle in which |
the side adjacent to the hyperbolic angle is associated with cosh while the side opposite is associated with sinh. However, since the point (1,1) on this hyperbola is a distance |
√2 from the origin, the normalization constant 1/√2 is necessary to define cosh and sinh by the lengths of the sides of the hyperbolic triangle. and the property that cosh |
t ≥ 1 for all t. The hyperbolic functions are periodic with complex period 2πi (πi for hyperbolic tangent and cotangent). The parameter t is not a circular angle, but |
rather a hyperbolic angle which represents twice the area between the x-axis, the hyperbola and the straight line which links the origin with the point (cosh t, sinh t) on |
the hyperbola. The function cosh x is an even function, that is symmetric with respect to the y-axis. The function sinh x is an odd function, that is −sinh x |
= sinh(−x), and sinh 0 = 0. The hyperbolic functions satisfy many identities, all of them similar in form to the trigonometric identities. In fact, Osborn's rule states that one |
can convert any trigonometric identity into a hyperbolic identity by expanding it completely in terms of integral powers of sines and cosines, changing sine to sinh and cosine to cosh, |
and switching the sign of every term which contains a product of 2, 6, 10, 14, ... sinhs. This yields for example the addition theorems the "double angle formulas" and |
the "half-angle formulas" The derivative of sinh x is cosh x and the derivative of cosh x is sinh x; this is similar to trigonometric functions, albeit the sign is |
different (i.e., the derivative of cos x is −sin x). The Gudermannian function gives a direct relationship between the circular functions and the hyperbolic ones that does not involve complex |
numbers. The graph of the function a cosh(x/a) is the catenary, the curve formed by a uniform flexible chain hanging freely under gravity. From the definitions of the hyperbolic sine |
and cosine, we can derive the following identities: These expressions are analogous to the expressions for sine and cosine, based on Euler's formula, as sums of complex exponentials. Since the |
exponential function can be defined for any complex argument, we can extend the definitions of the hyperbolic functions also to complex arguments. The functions sinh z and cosh z are |
The road to 'civilisation' is paved with bad intentions. Infestation, in'fes•ta'tion n. the state of being invaded or overrun by pests or parasites. Do people inhabit the lands and forests |
that they have been living in for thousands of years or do they infest them? The answer to this no-brainer of a question might well lie at the root of |
the problem being faced by the Jarawas in the Andaman Islands today. The video showing the Jarawa women dancing on the Andaman Trunk Road, apparently for food, is just the |
latest manifestation of a malaise that is so deep that one might well argue that there is no hope for the Jarawa. In 1965, the Ministry of Rehabilitation, Government of |
India, published an important document related to the Andaman & Nicobar Islands: ‘The Report by the Inter Departmental Team on Accelerated Development Programme for A&N Islands.' The contents of the |
report and their purpose were evident in the title itself — it laid out the roadmap for the development of these islands and set the stage for what was to |
happen over the decades that have followed. This little known report of less than a 100 pages in size is remarkable for the insight it provides into the thinking and |
the mindset of the times. There is what one might call a shocker on every page of this document and here is a just a sampling: Page 26: …The Jarawas |
have been uniformly hostile to all outsiders with the result that about half the Middle Andaman is treated as a Jarawa infested (emphasis added) area which is difficult for any |
outsider to venture… With the present road construction and the colonisation of the forest fringes, friction has become more frequent, and no month passes without a case of attack by |
the Jarawas. Page 69: The completion of the Great Andaman Trunk Road would go a long way to help in the extraction of forest produces... A nation that had just |
fought its way out of the ignominy of being a colony was well on the way to becoming a coloniser itself. And those that came in the way could only |
be pests or parasites infesting the forests that had valuable resources locked away from productive use. It is also pertinent to note here that in 1957 itself, more than a |
1000 sq. km of these “Jarawa infested” forests of South and Middle Andaman had already been declared protected as a Jarawa Tribal Reserve under the provisions of the Andaman and |
Nicobar Protection of Aboriginal Tribes Regulation (ANPATR) — 1956. The 1965 report was in complete violation, or was a result of complete ignorance of this legal protection to the Jarawa |
and the forests that they have inhabited for thousands of years. The seeds that were sown then have bloomed into myriad noxious weeds today and if one knows this history, |
the latest video that has generated so much heat is not in the bit surprising. Much space in the media, both print and electronic, has been occupied in the last |
few days by a range of claims and counter claims — about the date of the video, about the police involvement in its making, the role of tour operators and |
about fixing blame and responsibility. A little known fact that lies at the root of the issue has been all but forgotten — the existence of the Andaman Trunk Road, |
where this infamous video was shot about three years ago. The Andaman Trunk Road that the 1965 report offered as a good way of extracting resources from the forests of |
the Jarawa had been ordered shut by a Supreme Court order of 2002. It's been a decade now and in what can only be called audacious defiance, the administration of |
this little Union Territory has wilfully violated orders of the highest court of the land. A series of administrators have come and gone but contempt for the Supreme Court remains. |
Whenever asked about the order, the administration has tried to hide behind technicalities of interpreting the court order and arguing that the court had never ordered the road shut in |
the first place. They forget that in March 2003, a few months after the SC orders had been passed, they had themselves filed an affidavit with a plea to “permit |
the use/movement through the Andaman Trunk Road.” If it was not ordered shut, why the plea to keep it open? A few months later, in July 2003, the Supreme Court |
appointed Central Empowered Committee reiterated explicitly that the court orders include those for the closure of the ATR in those parts where it runs through the forests of the Jarawa |
Tribal Reserve. The A&N administration has clearly violated the court's order both in letter and in spirit. It is a spirit that was evocatively articulated by Dr. R.K. Bhattacharchaya, former |
Director of the Anthropological Survey of India, in a report he submitted to the Calcutta High Court in 2004. “The ATR”, he said, “is like a public thoroughfare through a |
private courtyard… In the whole of human history, we find that the dominant group for their own advantage has always won over the minorities, not always paying attention to the |
issue of ethics. Closure of the ATR would perhaps be the first gesture of goodwill on part of the dominant towards an acutely marginalized group almost on the verge of |
extinction”. The video in all its perversity offers us another opportunity, when all others in the past have been brushed aside either due to ignorance, arrogance or then sheer apathy. |
It's still not too late to make that ‘gesture of goodwill' because otherwise there will be many more such videos down the years and much worse will follow. The lessons |
from history are very clear on this. And it will hardly be a consolation that a few people will be left saying we told you so. (The writer is associated |
with Kalpavriksh, one of the three NGOs whose petition before the Supreme Court resulted in orders for the closure of the Andaman Trunk Road in 2002. He is also the |
I was taught at medical school to remember that “what’s common, is common”. So if a patient comes into clinic with a sore throat, the chances are it is simply that — a sore throat. Picking out the unusual diagnoses from seemingly common symptoms is one of the challenges of medicine, particularly when you are in general... |
symptom to see in clinic and usually has no sinister cause. But there are some unusual diagnoses that present as back pain for doctors and patients to be mindful of. While lower back pain can be caused by physical injury, or slipped discs, for five per cent of sufferers, the pain is due to inflammation caused by a form... |
young people. Since back pain is so common, the problem can go undiagnosed for years and lead to long-term damage. But it can be treated. Called axial spondyloarthritis, or axial SpA, it primarily affects the sacroiliac joint (the junction between the spine and the pelvis). Identifying the difference between this pain ... |
to look for. Typically, symptoms first appear in young people in the prime of their lives — this alone should ring an alarm bell — and often they have back pain or stiffness that has lasted for over three months. This is certainly a trigger to go to the GP. It is common for axial SpA patients to experience pain in the ... |
improves with exercise but then worsens with rest. If these symptoms sound like a familiar pattern, a trip to the doctor will be necessary for some blood tests as well as a referral to get an MRI scan. Diagnosis of this condition has been known to take as long as 10 years for some sufferers, but vigilance from doctors ... |
Solar-powered ion drive asteroid probe set for launch Not much va-va-voom, but very economical NASA has confirmed that the "Dawn" space probe to the asteroid belt will indeed launch on Saturday, ending speculation that the mission might be delayed. After launching, Dawn will spend four years in transit to the |
asteroids, circling the Sun twice and gaining a "gravity assist" on the way by making a close approach to Mars. Planned voyage of the Dawn space probe In 2011, Dawn will go into orbit around Vesta, one of the larger rock-like asteroids in the Belt. After around five months studying |
Vesta, the probe will depart in early 2012 and complete most of a further circuit round the Sun, finally catching up with Ceres in 2015 and going into orbit around it. Ceres is a large example of the other main asteroid type, thought to be largely icy in composition. The |
Dawn mission will be the first to go into orbit around a Belt asteroid, and also the first to orbit two different bodies. This unusual flight profile would be all but impossible, according to NASA, were it not for the spacecraft's innovative propulsion system. Dawn will lift off from Earth |
aboard a conventional, chemical Delta II rocket, but its journey to the asteroids will be propelled - apart from the helping hand from Martian gravity - by means of an ion drive. In an ion drive, thrust is still provided by throwing stuff out of the exhaust just as with |
a regular rocket. The difference is that rather than chemicals burning and expanding to throw themselves out of a combustion chamber, Dawn's Xenon propellant is squirted out of its back end using electrical power generated by solar panels. As one might expect, this produces an exceptionally feeble thrust; equivalent to |
about 0.02lb. The clever bit is that the ion engine achieves this thrust very economically, using only a tiny amount of propellant, because it accelerates the Xenon-plasma exhaust to such a high velocity. Dawn takes ages to squirt out a given amount of fuel, but when the ion drive finally |
does so it has achieved much more with it than a chemical rocket could have done. All this makes the multi-asteroid flightplan achievable within the NASA budget. Now that NASA has addressed some technical concerns, it appears that Dawn's Saturday launch is a go, and then it's just four years |
Cloudy outlook for climate models More aerosols - the solution to global warming? Climate models appear to be missing an atmospheric ingredient, a new study suggests. December's issue of the International Journal of Climatology from the Royal Meteorlogical Society contains a study of computer models used in climate for... |
the third mentioned is not entitled to the prefix Professor. Their topic is the discrepancy between troposphere observations from 1979 and 2004, and what computer models have to say about the temperature trends over the same period. While focusing on tropical latitudes between 30 degrees north and south (mostly to 20 d... |
mean temperature variability originates in the tropics" - the authors nevertheless crunched through an unprecedented amount of historical and computational data in making their comparison. For observational data they make use of ten different data sets, including ground and atmospheric readings at different heights. On... |
and Intercomparison. Some models were run several times, to produce a total of 67 realisations of temperature trends. The IPCC is the United Nation's Intergovernmental Panel on Climate Change and published their Fourth Assessment Report [PDF, 7.8MB] earlier this year. Their model comparison program uses a common set of... |
uncertainty for the data from the models. In aggregating the models, the uncertainty is derived from plugging the number 22 into the maths, rather than 67. The effect of using 67 would be to confine the latitude of error closer to the average trend - with the implication of making it harder to reconcile any discrepancy... |
and compare the observational and computed data, they also double this error interval. So to the burning question: on their analysis, does the uncertainty in the observations overlap with the results of the models? If yes, then the models are supported by the observations of the last 30 years, and they could be useful ... |
according to the study is no. Figure 1 in the published paper available here[PDF] pretty much tells the story. Douglass et al. Temperature time trends (degrees per decade) against pressure (altitutude) for 22 averaged models (shown in red) and 10 observational data sets (blue and green lines). Only at the surface are t... |
agree, within the uncertainties. While trends coincide at the surface, at all heights in the troposphere, the computer models indicate that higher trending temperatures should have occurred. And more significantly, there is no overlap between the uncertainty ranges of the observations and those of the models. In other ... |
Education is the transmission of civilization.~ William James Durant (1885–1981) and Ariel Durant, born Chaya Kaufman (1898 - 1981) After the murder of Benazir Bhutto, Pakistan dominated the news for a week or so but that has now faded. We were regaled with speculation about the danger to the world posed by an unstable... |
find it easy to integrate into society. It was in Pakistan that the Taliban (which took over the government of Afghanistan and provided shelter to Al Qaeda) were originally able to organize and build a foundation. A recent analysis on television suggests that the Taliban are direct descendants of protestors who instiga... |
missionary zeal in 19th century India. But Pakistan is also seen as a major bulwark in the "War on Terror" and has been the recipient of $5bn in US aid since the attack on the twin towers. Now the excitement has died down, Pakistan has dropped out of media consciousness but its problems remain. And one of its greatest ... |
is education. Like the rest of public life in Pakistan, the education system is subject to endemic corruption. And this should trouble the rest of the world because education in Pakistan is being exploited by fundamentalists in their drive to recruit new followers. When it was provided with American aid on a massive sc... |
the money to improving its education system. The World Bank has also allocated a separate $300mn specifically to support schools and colleges – but fearing that the money will disappear into a sink of corruption, it is reluctant to disburse the funds until proper control systems are put in place. These fears are justif... |
that invoices for supplies are inflated by as much as 30%, enabling millions of dollars to disappear. And in the education system, officials estimate that corruption taps 15% of intended expenditure. Little has been done to improve education in Pakistan. In the Punjab, for example, there are 63,000 state schools, of wh... |
structures. - 26,000 (41%) have no electricity. - 16,000 (25%) have no toilets. Many teachers see their jobs as sinecures and don't turn up to work, while local inspectors distrust the information provided by the ministry of education. Few schools have enough classrooms and some resort to teaching in the open air under... |
classroom with cracks in the walls and an unstable roof). Often they have to cope with only one quarter of the desks required. Understandably, parents are reluctant to send their children to these underfunded and under-supervised institutions. Two groups of educators have moved in to fill this vacuum: private schools a... |
most attention and generated hysteria in the press both inside and outside Pakistan. Some of them are run by fundamentalists, preach Jihad, and groom their students to be revolutionary fighters and suicide bombers The media in Pakistan and across the world, supported by wild estimates made by Pakistani police, have exa... |
by the World Bank and Harvard University has estimated that the true numbers of children being educated in madrassas represents a little less that 1% of children in the 5-19 age group. These figures must be put into context: - 33% of children are enrolled in state schools. - a further 12% are enrolled in private school... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.