RESPIRATION
The respiratory system (or ventilatory system) is the biological system that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood. This exchange process occurs in the alveolar region of the lungs.[1] Other animals, such as insects, have respiratory systems with very simple anatomical features, and in amphibians even the skin plays a vital role in gas exchange. Plants also have respiratory systems but the directionality of gas exchange can be opposite to that in animals. The respiratory system in plants also includes anatomical features such as holes on the undersides of leaves known as stomata.[2] he respiratory system lies dormant in the human fetus during pregnancy. At birth, the respiratory system becomes fully functional upon exposure to air, although some lung development and growth continues throughout childhood.[13] Pre-term birth can lead to infants with under-developed lungs. These lungs show incomplete development of the alveolar type II cells, cells that produce surfactant. The lungs of pre-term infants may not function well because the lack of surfactant leads to increased surface tension within the alveoli. Thus, many alveoli collapse such that no gas exchange can occur within some or most regions of an infant's lungs, a condition termed respiratory distress syndrome. Basic scientific experiments, carried out using cells from chicken lungs, support the potential for using steroids as a means of furthering development of type II alveolar cells.[14] In fact, once a pre-mature birth is threatened, every effort is made to delay the birth, and a series of steroid shots is frequently administered to the mother during this delay in an effort to promote lung growth.[15] Disease
Disorders of the respiratory system can be classified into four general areas:
Obstructive conditions (e.g., emphysema, bronchitis, asthma) Restrictive conditions (e.g., fibrosis, sarcoidosis, alveolar damage, pleural effusion) Vascular diseases (e.g., pulmonary edema, pulmonary embolism, pulmonary hypertension) Infectious, environmental and other "diseases" (e.g., pneumonia, tuberculosis, asbestosis, particulate pollutants):
Coughing is of major importance, as it is the body's main method to remove dust, mucus, saliva, and other debris from the lungs. Inability to cough can lead to infection. Deep breathing exercises may help keep finer structures of the lungs clear from particulate matter, etc. The respiratory tract is constantly exposed to microbes due to the extensive surface area, which is why the respiratory system includes many mechanisms to defend itself and prevent pathogens from entering the body. Disorders of the respiratory system are usually treated internally by a pulmonologist and Respiratory Therapist. Plants Plants use carbon dioxide gas in the process of photosynthesis, and exhale oxygen gas as waste. The chemical equation of photosynthesis is 6 CO2 (carbon dioxide) and 6 H2O (water) and that makes 6 O2 (oxygen) and C6H12O6 (glucose). What is not expressed in the chemical equation is the capture of energy from sunlight which occurs. Photosynthesis uses electrons on the carbon atoms as the repository for that energy. Respiration is the opposite of photosynthesis. It reclaims the energy to power chemical reactions in cells. In so doing the carbon atoms and their electrons are combined with oxygen forming a gas which is easily removed from both the cells and the organism. Plants use both processes, photosynthesis to capture the energy and respiration to use it.
Plant respiration is limited by the process of diffusion. Plants take in carbon dioxide through holes on the undersides of their leaves known as stoma or pores. However, most plants require little air.[citation needed] Most plants have relatively few living cells outside of their surface because air (which is required for metabolic content) can penetrate only skin deep. However, most plants are not involved in highly aerobic activities, and thus have no need of these living cells.
#!/usr/bin/python #Author : [email protected] import urllib max_limit=5 def get_page(url):#This function is just to return the webpage contents; the source of the webpage when a url is given. try: f = urllib.urlopen(url) page = f.read() f.close() #print page return page except: return "" return "" def union(a,b):#The union function merges the second list into first, with out duplicating an element of a, if it's already in a. Similar to set union operator. This function does not change b. If a=[1,2,3] b=[2,3,4]. After union(a,b) makes a=[1,2,3,4] and b=[2,3,4] for e in b: if e not in a: a.append(e) def get_next_url(page): start_link=page.find("a href") if(start_link==-1): return None,0 start_quote=page.find('"',start_link) end_quote=page.find('"',start_quote+1) url=page[start_quote+1:end_quote] return url,end_quote def get_all_links(page): links=[] while(True): url,n=get_next_url(page) page=page[n:] if url: links.append(url) else: break return links def Look_up(index,keyword):#This function is for given an index, it finds the keyword in the index and returns the list of links #f=[] if keyword in index: return index[keyword] return [] #The format of element in the index is
- ]
def add_to_index(index,url,keyword):
if keyword in index:
if url not in index[keyword]:
index[keyword].append(url)
return
index[keyword]=[url]
def add_page_to_index(index,url,content):#Adding the content of the webpage to the index
for i in content.split():
add_to_index(index,url,i)
def compute_ranks(graph):#Computing ranks for a given graph -> for all the links in it
d=0.8
numloops=10
ranks={}
npages=len(graph)
for page in graph:
ranks[page]=1.0/npages
for i in range(0,numloops):
newranks={}
for page in graph:
newrank=(1-d)/npages
for node in graph:
if page in graph[node]:
newrank=newrank+d*ranks[node]/len(graph[node])
newranks[page]=newrank
ranks=newranks
return ranks
def Crawl_web(seed):#The website to act as seed page is given as input
tocrawl=[seed]
crawled=[]
index={}
graph={}#new graph
global max_limit
while tocrawl:
p=tocrawl.pop()
if p not in crawled:#To remove the looping, if a page is already crawled and it is backlinked again by someother link we are crawling, we need not crawl it again
max_limit-=1
print max_limit
if max_limit<=0:
break
c=get_page(p)
add_page_to_index(index,p,c)
f=get_all_links(c)
union(tocrawl,f)
graph[p]=f
crawled.append(p)#As soon as a link is crawled it is appended to crawled. In the end when all the links are over, we will return the crawled since it contains all the links we have so far
return crawled,index,graph #Returns the list of links
#print index
def QuickSort(pages,ranks):#Sorting in descending order
if len(pages)>1:
piv=ranks[pages[0]]
i=1
j=1
for j in range(1,len(pages)):
if ranks[pages[j]]>piv:
pages[i],pages[j]=pages[j],pages[i]
i+=1
pages[i-1],pages[0]=pages[0],pages[i-1]
QuickSort(pages[1:i],ranks)
QuickSort(pages[i+1:len(pages)],ranks)
def Look_up_new(index,ranks,keyword):
pages=Look_up(index,keyword)
print '\nPrinting the results as is with page rank\n'
for i in pages:
print i+" --> "+str(ranks[i])#Displaying the lists, so that you can see the page rank along side
QuickSort(pages,ranks)
print "\nAfter Sorting the results by page rank\n"
it=0
for i in pages:#This is how actually it looks like in search engine results - > sorted by page rank
it+=1
print str(it)+'.\t'+i+'\n'
#print index
print "Enter the seed page"
seed_page=raw_input()
print "Enter What you want to search"
search_term=raw_input()
try:
print "Enter the depth you wanna go"
max_limit=int(raw_input())
except:
f=None
print '\nStarted crawling, presently at depth..'
crawled,index,graph=Crawl_web(seed_page)#printing all the links
ranks=compute_ranks(graph)#Calculating the page ranks
Look_up_new(index,ranks,search_term)