You will be presented with the full text of a science research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
the knowledge of the lateral distribution function ( ldf ) of charged particles from extensive air shower ( eas ) is vital for experiments in the field of ultra - high energy cosmic ray ( uhecr ) studying .
it is ldf that defines main shower parameters such as @xmath4   ( charged particle density at the distance @xmath5  m from the core ) and thus   primary energy .    in this paper
we consider parameters of individual ldfs resulted from revision of high energy events registered at the yakutsk eas array .
the aim of this work is to trace possible correlation between parameters of individual showers and their arrival directions on the sky , especially for galactic planes and for the region with significantly increased uhecr flux , detected by yakutsk group  @xcite .
for the analysis we selected showers with @xmath6  ev , with zenith angles @xmath7 and with core lying well within the boundaries of the array , to make sure that shower core is found correctly .    at the yakutsk eas array ,
approximation proposed by greisen  @xcite is used for primary data processing : @xmath8 where @xmath9 is moiere radius and slope parameter @xmath10 .    in the work by glushkov et al  @xcite ,
an updated approximation was proposed , that demonstrated better description of experimental points at large distances from the core ( @xmath11  m ) : @xmath12 where @xmath13 .    in equations ( [ eq : nkg ] ) and ( [ eq : glushkov ] ) the slope parameter @xmath14 is derived from average ldf . while it describes most of showers quite well , it certainly fails doing so in dozen number of events . during revision we performed @xmath15-fitting of functions ( [ eq : nkg ] ) and ( [ eq : glushkov ] ) normalized to @xmath4 on experimental data for each
selected shower with free parameters @xmath4 and @xmath16 .    the value @xmath17 could give a hint of possible astrophysical aspect of the slope parameter in functions ( [ eq : nkg ] ) and ( [ eq : glushkov ] ) .
as seen on fig.[slope_galaxy ] , comparison to galactic coordinates showed no correlation between @xmath18 and galaxy plane .
vs galactic latitude .
marked stripe @xmath19 is galaxy plane.,scaledwidth=45.0% ]    to trace possible dependency on astrophysical coordinates , we selected a `` stripe '' of @xmath20 width along declination and divided it into `` chunks '' of @xmath21h each along right ascension .
such a stripe was selected to exclude zenith - angular dependency . averaged @xmath18 values in each chunk are presented in table  [ tab : slope ] in comparison to averaged value in the rest chunks of the stripe .
vs astrophysical coordinates.,scaledwidth=45.0% ]    [ cols="^,^,^,^,^,^,^ " , ]         obtained @xmath22 values did not allow us to make juxtaposition with celestial coordinates as for functions ( [ eq : nkg ] ) and ( [ eq : glushkov ] ) .
revised parameters of individual lateral distribution functions in greisen s ( ( [ eq : nkg ] ) and ( [ eq : glushkov ] ) ) approximation showed no correlation neither with galactic plane , nor with the region of uhecr region excess . from table  [ tab : slope ] it is seen , that increased @xmath18 in the region of interest ( @xmath23 ) is not significant and the whole picture is spoiled by poor statistics .
difficulties in estimation of @xmath22 did now allow us to use scaling approximation  ( [ eq : lagutin ] ) in such analysis . in the work by msu eas group
@xcite authors have faced similar obstacles in @xmath22 determination .
it is worth mentioning , that kascade - grande group successfully used scaling formalism for estimation of muon density in air showers  @xcite . besides , scintillation detectors used at the yakutsk array may lead to sloping of charged particle distribution caused by registration of atmospheric muons and electrons from muon decay . if we consider this fact together with zenith - angular dependence of @xmath22 more closely , we can obtain more plausible estimation of this parameter .
a.  a.  lagutin , r.  i.  raikin , n.  inoue and a.  misaki .
electron lateral distribution in air showers : scaling formalism and its implications
. _ journal of physics g : nuclear and particle physics _
, 28:12591274 , 2002 .
a shape of lateral distribution for charged particles in events with energy above @xmath0  ev is considered . 
 two methods were used for individual ldf parametrization . in the first approach , the index of power was determined for generalized greisen - linsley approximation . in second , mean 
 square radius of the shower was determined for approximation proposed by lagutin et al . 
 comparison of resulted parameters is presented for individual events arrived from different celestial regions   galactic planes and the region with increased flux of particles with @xmath1  ev ( according to yakutsk array ) : @xmath2 right ascension ; @xmath3 declination .